Na+-independent choline transport in rat retinal capillary endothelial cells

Masatoshi Tomi, Kanako Arai, Masanori Tachikawa, Ken Ichi Hosoya

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

The purpose of this study was to clarify the mechanism of the inner blood-retinal barrier (inner BRB) transport of choline and examine the choline uptake ability of rat choline transporter-like protein (CTL) 1. The transcript level of CTL1 in a conditionally immortalized rat retinal capillary endothelial cell line (TR-iBRB2) is more than 100-fold greater than that of CTL3 and CTL4, and no expression of organic cation transporter (OCT) mRNA was detected. The apparent influx permeability clearance of [3H]choline in the rat retina was found to be 271 μl/(min · g retina). The [ 3H]choline uptake by TR-iBRB2 cells was Na+-independent, potential-dependent, and concentration-dependent with Michaelis-Menten constants of 6.44 μM and 99.7 μM, and inhibited by several organic cations but not tetraethylammonium. The inhibition of CTL1 mRNA by small interfering RNA had little effect on the [3H]choline uptake by TR-iBRB2 cells. Rat CTL1-expressing Xenopus laevis oocytes exhibited an increase in the [ 3H]choline uptake by 45% compared with a control. In conclusion, our findings are consistent with Na+-independent choline transport being the mechanism for blood-to-retina transport of choline at the inner BRB. Although rat CTL1 expression is associated with the choline uptake, CTL1 does not play a major role in the choline uptake at the inner BRB.

Original languageEnglish
Pages (from-to)1833-1842
Number of pages10
JournalNeurochemical Research
Volume32
Issue number11
DOIs
Publication statusPublished - 2007 Nov
Externally publishedYes

Fingerprint

Endothelial cells
Choline
Rats
Endothelial Cells
Blood-Retinal Barrier
Blood
Retina
Cations
Messenger RNA
Tetraethylammonium
Xenopus laevis
Small Interfering RNA
Oocytes
Permeability
Cell Line

Keywords

  • Choline
  • Choline transporter-like protein (CTL)
  • Inner blood-retinal barrier
  • Transporter

ASJC Scopus subject areas

  • Neuroscience(all)
  • Biochemistry

Cite this

Na+-independent choline transport in rat retinal capillary endothelial cells. / Tomi, Masatoshi; Arai, Kanako; Tachikawa, Masanori; Hosoya, Ken Ichi.

In: Neurochemical Research, Vol. 32, No. 11, 11.2007, p. 1833-1842.

Research output: Contribution to journalArticle

Tomi, Masatoshi ; Arai, Kanako ; Tachikawa, Masanori ; Hosoya, Ken Ichi. / Na+-independent choline transport in rat retinal capillary endothelial cells. In: Neurochemical Research. 2007 ; Vol. 32, No. 11. pp. 1833-1842.
@article{318067e4a6b44d49925b5307d1bb3c95,
title = "Na+-independent choline transport in rat retinal capillary endothelial cells",
abstract = "The purpose of this study was to clarify the mechanism of the inner blood-retinal barrier (inner BRB) transport of choline and examine the choline uptake ability of rat choline transporter-like protein (CTL) 1. The transcript level of CTL1 in a conditionally immortalized rat retinal capillary endothelial cell line (TR-iBRB2) is more than 100-fold greater than that of CTL3 and CTL4, and no expression of organic cation transporter (OCT) mRNA was detected. The apparent influx permeability clearance of [3H]choline in the rat retina was found to be 271 μl/(min · g retina). The [ 3H]choline uptake by TR-iBRB2 cells was Na+-independent, potential-dependent, and concentration-dependent with Michaelis-Menten constants of 6.44 μM and 99.7 μM, and inhibited by several organic cations but not tetraethylammonium. The inhibition of CTL1 mRNA by small interfering RNA had little effect on the [3H]choline uptake by TR-iBRB2 cells. Rat CTL1-expressing Xenopus laevis oocytes exhibited an increase in the [ 3H]choline uptake by 45{\%} compared with a control. In conclusion, our findings are consistent with Na+-independent choline transport being the mechanism for blood-to-retina transport of choline at the inner BRB. Although rat CTL1 expression is associated with the choline uptake, CTL1 does not play a major role in the choline uptake at the inner BRB.",
keywords = "Choline, Choline transporter-like protein (CTL), Inner blood-retinal barrier, Transporter",
author = "Masatoshi Tomi and Kanako Arai and Masanori Tachikawa and Hosoya, {Ken Ichi}",
year = "2007",
month = "11",
doi = "10.1007/s11064-007-9367-0",
language = "English",
volume = "32",
pages = "1833--1842",
journal = "Neurochemical Research",
issn = "0364-3190",
publisher = "Springer New York",
number = "11",

}

TY - JOUR

T1 - Na+-independent choline transport in rat retinal capillary endothelial cells

AU - Tomi, Masatoshi

AU - Arai, Kanako

AU - Tachikawa, Masanori

AU - Hosoya, Ken Ichi

PY - 2007/11

Y1 - 2007/11

N2 - The purpose of this study was to clarify the mechanism of the inner blood-retinal barrier (inner BRB) transport of choline and examine the choline uptake ability of rat choline transporter-like protein (CTL) 1. The transcript level of CTL1 in a conditionally immortalized rat retinal capillary endothelial cell line (TR-iBRB2) is more than 100-fold greater than that of CTL3 and CTL4, and no expression of organic cation transporter (OCT) mRNA was detected. The apparent influx permeability clearance of [3H]choline in the rat retina was found to be 271 μl/(min · g retina). The [ 3H]choline uptake by TR-iBRB2 cells was Na+-independent, potential-dependent, and concentration-dependent with Michaelis-Menten constants of 6.44 μM and 99.7 μM, and inhibited by several organic cations but not tetraethylammonium. The inhibition of CTL1 mRNA by small interfering RNA had little effect on the [3H]choline uptake by TR-iBRB2 cells. Rat CTL1-expressing Xenopus laevis oocytes exhibited an increase in the [ 3H]choline uptake by 45% compared with a control. In conclusion, our findings are consistent with Na+-independent choline transport being the mechanism for blood-to-retina transport of choline at the inner BRB. Although rat CTL1 expression is associated with the choline uptake, CTL1 does not play a major role in the choline uptake at the inner BRB.

AB - The purpose of this study was to clarify the mechanism of the inner blood-retinal barrier (inner BRB) transport of choline and examine the choline uptake ability of rat choline transporter-like protein (CTL) 1. The transcript level of CTL1 in a conditionally immortalized rat retinal capillary endothelial cell line (TR-iBRB2) is more than 100-fold greater than that of CTL3 and CTL4, and no expression of organic cation transporter (OCT) mRNA was detected. The apparent influx permeability clearance of [3H]choline in the rat retina was found to be 271 μl/(min · g retina). The [ 3H]choline uptake by TR-iBRB2 cells was Na+-independent, potential-dependent, and concentration-dependent with Michaelis-Menten constants of 6.44 μM and 99.7 μM, and inhibited by several organic cations but not tetraethylammonium. The inhibition of CTL1 mRNA by small interfering RNA had little effect on the [3H]choline uptake by TR-iBRB2 cells. Rat CTL1-expressing Xenopus laevis oocytes exhibited an increase in the [ 3H]choline uptake by 45% compared with a control. In conclusion, our findings are consistent with Na+-independent choline transport being the mechanism for blood-to-retina transport of choline at the inner BRB. Although rat CTL1 expression is associated with the choline uptake, CTL1 does not play a major role in the choline uptake at the inner BRB.

KW - Choline

KW - Choline transporter-like protein (CTL)

KW - Inner blood-retinal barrier

KW - Transporter

UR - http://www.scopus.com/inward/record.url?scp=34848825899&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=34848825899&partnerID=8YFLogxK

U2 - 10.1007/s11064-007-9367-0

DO - 10.1007/s11064-007-9367-0

M3 - Article

C2 - 17520363

AN - SCOPUS:34848825899

VL - 32

SP - 1833

EP - 1842

JO - Neurochemical Research

JF - Neurochemical Research

SN - 0364-3190

IS - 11

ER -